PHAGE TAXONOMY 437 



known phage strains. If it cannot be related to a known phage 

 strain, type speciniens of the phage and a suitable host bacterium 

 should be placed in the ATCC or other culture collection and this 

 fact be recorded in the published paper. The type specimens 

 should be prepared for storage either as lyophilized specimens or 

 in a suitable fluid medium in sealed tubes and 10 to 20 specimens 

 should be included to minimize maintenance problems in the 

 collection. In the case of unstable phage strains the possibility 

 of preserving typing antisera should be considered as an alter- 

 native to indefinite maintenance of the phage strains in culture 

 collections. It should be recognized that publications in the 

 field of biology may be of relatively little value unless the bio- 

 logical material used is readily available for study by other in- 

 vestigators. 



8. Summary 



The taxonomy and nomenclature of bacteriophages is in an 

 unsatisfactory state at the present time for a number of reasons. 

 There are no generally applicable taxonomic criteria available 

 for defining the limits of the species and the genus in the bac- 

 teriophages. Tentative suggestions for such criteria have been 

 proposed for further investigation. Because of the lack of infor- 

 mation about the phylogeny of phages it is not possible to con- 

 sider taxonomic categories above the genus level. The relation- 

 ships among different groups of phages, of phages to other viruses 

 and of phages to their host cells are quite obscure at present. 

 Because of this it would seem that the use of a formal Linnaean 

 binomial nomenclature would be premature. The importance 

 of maintaining type specimens for the use of other investigators is 

 emphasized. Much of the phage literature is worthless for 

 taxonomic purposes because of the impossibility of identifying 

 the phage strains that were used. 



